PageRank wasn't that much better. It was better and the word spread. Google also had a very clean UI at a time where websites like Excite and Yahoo had super bloated pages.
That was the differentiation. What makes you think AI companies can't find moats similar to Google's? The right UX, the right model and a winner can race past everyone.
I remember the pre-Google days when AltaVista was the best search engine, just doing keyword matching, and of course you would therefore have to wade through pages of results to hopefully find something of interest.
Google was like night & day. PageRank meant that typically the most useful results would be on the first page.
That was the differentiation. What makes you think AI companies can't find moats similar to Google's? The right UX, the right model and a winner can race past everyone.